The supporters of Nottingham Forest and Derby, traditionally fierce rivals, were united yesterday as they paid their respects to Brian Clough.

The legendary manager - who played for both Sunderland and Middlesbrough and who died of cancer on Monday - guided Forest to back-to-back European Cup victories and led Derby to the championship.

Forest will keep their City Ground open around the clock so that supporters can continue to pay their respects to Clough. And an internet book of condolence has been opened on the club's official website, www.nottinghamforest.co.uk

A written book of condolence has already been established at the Council House in both Nottingham and Derby. Fans can also lay flowers at County's Pride Park Stadium.

The Mayor of Derby, Ruth Skelton, said: "It is rare that the cities of Derby and Nottingham are united but their sense of loss will be palpable."

Rams chief executive Jeremy Keith said: "Brian was this club's greatest ever manager and, in the eyes of Rams supporters, the best the world has ever seen."

The club will pay tribute to Clough with a minute's silence ahead of the home game against Wigan this weekend and is also seeking fans' ideas on a permanent memorial.

Forest's current manager Joe Kinnear paid tribute to Clough, saying he was probably more famous than Robin Hood. "Brian Clough was a unique manager who took Nottingham Forest from obscurity to the First Division title and then two successive European Cups.

"His achievements with the club are everywhere to be seen around the ground and I have no doubt that he is up there with the best managers of all time.

"He is as synonymous with Nottingham as Robin Hood is and Cloughie is arguably the more famous of the two! In the short space of time I have been in Nottingham, I have only met him a few times, but I always found him to be a most loveable guy and great company. They certainly don't make them like Cloughie any more."

Former Middlesbrough skipper Gordon Jones told Boro's official website, www.mfc.co.uk: "He could be very forthright, but he had a heart of gold. I'm absolutely shocked and saddened."